The effect of controlled respiration on parameters of heart rate variability

To assess whether controlling the respiratory rate affects the various parameters of heart rate variability in normal subjects, 26 healthy young subjects were studied with spontaneous and controlled respiration at 15 breaths/minute. The mean, standard deviation, and mean of the differences of consecutive RR intervals (MSD msec), the absolute power of the mayer wave sinus arrhythmia (0.05-0.15 Hz) (MWSA) and respiratory sinus arrhythmia (0.16-0.35 Hz) (RSA), and ratio of MWSA (%MSWA) and RSA (%RSA) to total power were calculated. A decrease is demonstrated in the SD and MWSA with controlled respiration which shows a decrease in the sympathetic function. There is no change in the parasympathetic system, with no change in either MSD or RSA. The ratios %MWSA and %RSA, however, change because of changes in the total power of the power spectrum